Comments on: Last Time CO2 Levels Hit 400 Parts Per Million & Humans Were Alive — Never

Comments on: Last Time CO2 Levels Hit 400 Parts Per Million & Humans Were Alive — Never http://cleantechnica.com/2013/05/13/last-time-co2-levels-hit-400-parts-per-million-humans-were-alive-never/ Clean Tech News & Views: Solar Energy News. Wind Energy News. EV News. & More. Sun, 28 Dec 2014 14:06:00 +0000 hourly 1 http://wordpress.org/?v=4.0.1 By: US Coal Exports: "The Worst Of The Worst" | PlanetSave http://cleantechnica.com/2013/05/13/last-time-co2-levels-hit-400-parts-per-million-humans-were-alive-never/#comment-163856 Thu, 30 May 2013 20:53:18 +0000 http://cleantechnica.com/?p=51680#comment-163856 […] high set in 1981. This, at a time when global atmospheric levels of CO2 have reached levels never before seen in human […]

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